Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Electrical & Electronics Expert

1) a) A 350KW, 220V, 4 pole, lap wound dc generator has the 600 armature conductors. If brushes are given a lead of 8 electrical degrees, find the number of demagnetizing and cross magnetizing ampere turns per pole. Shunt field current may be neglected.

b) describe what is commutation? Describe the various methods for improving the commutation.

2)  A short shunt compound generator supplies the current of 150A at the voltage of 230V.The resistance of shunt field is 30?, and the series field is 0.01 ?, armature is 0.02 ?, the total brush drop is 2V and the iron and friction loss is amount to 1.3KW. Determine

a) Generated E.M.F

b) Copper loss

c) Output power of the prime mover driving the generator

d) Generator efficiency.

3) The Hopkinson’s test on two shunt machines gave the following results.
Line voltage = 230V, line current excluding the field current = 25A; motor armature current = 250A; field current = 2A, Determine the efficiency of each machine under this load condition. Provided the armature resistance of each machine is 0.2 Ω.

4) a) Describe the Ward Leonard type of speed control with the help of  suitable diagram.

b) A dc shunt generator delivers a 25KW at 220V while running at 1200 rpm. Rf = 120 Ω, Ra = 0.2 Ω. Find the speed of the machine running as a dc shunt motor taking 25KW at 220V. Enable 1V per brush contact drop.

5) a) Describe the approximate equivalent circuit of the transformer

b) Draw the phasor diagram for the transformer loaded with:

i) Inductive load

ii) Resistive load.

6) Determine the all day efficiency of the 1000KVA transformer whose copper loss and iron losses at full load are 3.5KW and 5.2KW respectively. During the day of 24hrs it is loaded as follows.

Number of hrs                  Load in KW                       Power factor

4                                         1000                                   0.9

8                                          700                                    0.7

8                                         400                                     0.5

4                                          ---                                         ---


7) Deduce the equation for saving of the Cu for an autotransformer. Specify its different limitations and applications.

8) a) Describe the 3 phase to 2 phase and the 3 phase to 6 phase transformer conversion.

b) Describe the Scott connection in a transformer in detail.

9) describe what is a synchro? Describe the operation of a synchro as an error detector in detail.

10) Deduce the torque equation of the PMBL DC motor describing all the parameters included in it.

Electrical & Electronics, Engineering

  • Category:- Electrical & Electronics
  • Reference No.:- M913031

Have any Question? 


Related Questions in Electrical & Electronics

An oscillator by definition is a source no input that

An oscillator by definition is a source (no input) that generates a sinusoid of a certain frequency ω0. Therefore an oscillator is a system whose zero-input response is a sinusoid of the desired frequency. Find the trans ...

1 assume fixed-sized packets arrive at a router with a rate

1. Assume fixed-sized packets arrive at a router with a rate of three packets per second. Show how the router can use the leaky bucket algorithm to send out only two packets per second. What is the problem with this appr ...

1 assume alice needs to send an e-mail to bob explain how

1. Assume Alice needs to send an e-mail to Bob. Explain how the confidentiality of the e-mail is achieved using S/MIME. 2. When we talk about authentication in SSL, do we mean message authentication or entity authenticat ...

1 what is the significance of a nonzero net right-lateral

1. What is the significance of a nonzero net right-lateral differential of and normal to the z-direction at a point in space? 2. If a pair of E and B at a point satisfies Faraday's law in differential form, does it neces ...

A periodic signal xt is expressed by the following fourier

A periodic signal x(t) is expressed by the following Fourier series: a. Sketch the amplitude and phase spectra for the trigonometric series. b. By inspection of spectra in part (a), sketch the exponential Fourier series ...

Assume we have a very simple message digest our unrealistic

Assume we have a very simple message digest. Our unrealistic message digest is just one number between 0 and 25. The digest is initially set to 0. The cryptographic hash function adds the current value of the digest to t ...

1 in logisim implement an 8-to-1 mux using 2 4-to-1 muxes

1. In Logisim implement an 8-to-1 MUX using 2 4-to-1 MUXes and a 2-to-1 MUX. 2. In Logisim implement an 8-to-1 MUX using 4 2-to-1 MUXes and a 4-to-1 MUX. 3. In Logisim implement a circuit similar to the one in figure 8-1 ...

1 state the relationship between polarization current

1. State the relationship between polarization current density and electric field intensity. How is it taken into account in Maxwell's equations? 2. What is the revised definition of D? 3. State the relationship between ...

A circular loop antenna of radius 1 m in free space carries

A circular loop antenna of radius 1 m in free space carries a uniform current (a) Calculate the amplitude of the electric field intensity at a distance of 10 km in the plane of the loop. (b) Calculate the radiation resis ...

An infinite plane sheet lying in the plane carries a

An infinite plane sheet lying in the plane carries a current of uniform density Find the magnetic field intensities adjacent to the sheet and on either side of it. What is the polarization of the field?

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro

Describe what you learned about the impact of economic

Describe what you learned about the impact of economic, social, and demographic trends affecting the US labor environmen